Controllable Chemical Injection For Multiple Zone Completions

ABSTRACT

This disclosure relates to an apparatus and method for controlling the amount of an additive injected into production fluid in a plurality of production zones. The injection devices may be dynamically controlled such that a central or decentralized control system may instruct a plurality of additive injection assemblies to inject additive, wherein different additive and/or different amounts of additive may be injected in the production fluid in the plurality of production zones. The apparatus includes one or more controllers to send operating commands to downhole regulating elements that may control the amount of additive being injected directly or indirectly.

BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure

This disclosure relates generally to oilfield operations and more particularly to an additive injection system and methods of employing same.

2. Background of the Art

During hydrocarbon recovery operations, production tubing, pipelines, valves and related equipment may be exposed to substances that corrode, degrade or otherwise reduce their efficiency or service life. Thus, it may be advantageous to treat such equipment with corrosion inhibitors, scale inhibitors, paraffin inhibitors, hydrate inhibitors, demulsifiers, and the like, and mixtures thereof. This disclosure provides, in part, enhanced additive injection systems and methods suitable for such uses.

SUMMARY OF THE DISCLOSURE

In aspects, this disclosure is related to an apparatus and method for controlling the amount of an additive injected into a plurality of production zones, whereby the amount of additive may be dynamically adjusted between the different production zones. The apparatus includes one or more controllers to send operating commands to downhole regulating elements that may control the amount of additive being injected.

In one aspect, the invention is an apparatus for controlling an amount of an additive injected into a plurality of production zones or points within a single production zone, including: a plurality of additive injector assemblies, wherein each injector assembly comprises: an umbilical disposed in a wellbore intersecting a production zone, at least one injector device adapted to receive the additive from the umbilical and disposed within the production zone, and a regulating element associated with the at least one injector that is responsive to a control signal; and at least one controller configured to transmit a plurality of control signals to the plurality of regulating elements.

In another embodiment, the invention is A method for controlling an amount of an additive injected into a plurality of production zones, including: introducing a plurality of additive injection assemblies into a plurality of wellbore zones; wherein each of the plurality additive injection assemblies comprises: an umbilical disposed in a wellbore intersecting a production zone, at least one injector adapted to receive the additive from the umbilical and disposed within the production zone, and a regulating element associated with the at least one injector and responsive to a control signal, wherein the regulating element controls the amount of additive introduced to the wellbore zone, and activating at least one controller in communication with the plurality of regulating elements send at least one signal to at least one of the plurality of regulating elements.

In still another aspect, the invention is a a method for controlling an amount of an additive injected into a plurality of production zones, including: supplying the additive to a plurality of injectors; wherein each of the plurality of injectors is disposed within one of the plurality of production zones; transmitting a plurality of control signals from at least one controller to a plurality of regulating elements, wherein each of the plurality of regulating elements is associated with at least one of the plurality of injectors; and injecting the amount of additive into the plurality of production zones responsive to the associated control signal. The method of claim 13, wherein the amount of additive introduced to at least one of the plurality of production zones is dissimilar to the amount of additive introduced to another one of the plurality of production zones.

Examples of the more important features of the disclosure have been summarized rather broadly in order that the detailed description thereof that follows may be better understood and in order that the contributions they represent to the art may be appreciated. There are, of course, additional features of the disclosure that will be described hereinafter and which will form the subject of the claims appended hereto.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed understanding of this disclosure, reference should be made to the following detailed description of the one mode embodiments, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals, wherein:

FIG. 1 schematically illustrates one embodiment according to this disclosure;

FIG. 2 schematically illustrates one embodiment of the controller for one embodiment according to this disclosure

FIG. 3 schematically illustrates one embodiment of the invention employed in two separate wellbores;

FIG. 4 schematically illustrates one embodiment of the invention employed in an offshore well have multiple bores diverging from a single wellbore;

FIG. 5 schematically illustrates one embodiment of the invention employed in a single wellbore; and

FIG. 6-10 schematically illustrate details of five exemplary embodiments of an injection device.

DETAILED DESCRIPTION OF THE DISCLOSURE

Referring initially to FIG. 1, there is schematically shown one embodiment of an apparatus for controlling an amount of additive introduced into production fluid or additive injector assembly 100 (hereinafter “assembly 100”)

The assembly 100 may be utilized to introduce or inject a variety of chemicals or additives into the production zone 190 to control, among other things, corrosion, scale, paraffin, emulsion, hydrates, hydrogen sulfide, asphaltenes, inorganics and other harmful substances. As used herein, the term “additive” generally refers to an engineered fluid that is formulated to perform a desired task. The additive(s) may be mixed with a base fluid such as water or oil to form what will hereafter be referred to as “injection fluid(s).” Injection fluid(s) may include liquids and/or gases. The assembly 100 may be configured to supply precise amounts of an additive or a mixture of additives to prevent, mitigate or otherwise lessen the harm caused by these substances. The assembly 100 may also be configured to periodically or continuously monitor the actual amount of the additives being dispensed, determine the effectiveness of the dispensed additives, and vary the amount of dispense additives as needed to maintain one or more parameters of interest within predetermined ranges or at specified values.

It should be understood that relatively small amounts of additives are injected into the production fluid during operation. Accordingly, considerations such as precision in dispensing additives may be more relevant than mere volumetric capacity. In embodiments, the flow rate for an additive injected using this disclosure may be at a rate such that the additive is present at a concentration of from about 1 parts per million (ppm) to about 10,000 ppm in the fluid being treated. In other embodiments, the flow rate for an additive injected using this disclosure may be at a rate such that the additive is present at a concentration of from about 1 ppm to about 500 ppm in the fluid being treated.

In one embodiment, the additive injector assembly 100 includes an additive reservoir 110, an umbilical 120, a regulating element 130, an injection device 140, and a communication link 150. Additive 105 stored in additive reservoir 110 may be supplied through umbilical 120 to injection device 140. Additive 105 may be supplied directly from umbilical 120 to injection device 140 or regulating element 130 may be interposed between umbilical 120 and injection device 140. The amount of additive supplied into production fluid 160 within the production zone 190 of well bore 170 may be regulated by regulating element 130. Regulation may be provided by limiting flow of additive 105 through regulating element 130 or by restricting the flow of additive 105 through injection device 140.

The well bore 170 may have one or more production zones 190 for draining hydrocarbons from the formation (“produced fluids” or “production fluid”). A production tubular 165 may be used to convey the fluid from the production zones to the wellhead (not shown). Wellhead equipment and production well equipment are well known and thus are not described in greater detail.

Regulating element 130 may receive a signal through communications link 150 that determines how much additive 105 may be injected into the production fluid 160. Outside the well bore 170, a controller 180 may be connected to multiple communication links 150 coming from multiple additive injector assemblies 100. Controller 180 may be adapted to provide instructions to the plurality of regulating elements 130 such that each well bore 170 receives the same, similar, or different amounts of additive 105 as other well bores 170.

Umbilical 120 may be disposed inside or outside production tubular 165. Regulating element 130 may include a valve to control the flow of additive flowing from the umbilical 120 to injection device 140. In another embodiment regulating element 130 may actuate valves or other devices that are part of the injection device 140 to control the flow of additive flowing from the umbilical 120 to the production fluid 160.

Injection device 140 may be a pump such as a positive displacement pump, a centrifugal pump, a piston-type pump, or other suitable device for pumping fluid. Injection device 140 may have one or more injectors, which may be controlled in common or separately by the regulating element 130.

In one embodiment, additive reservoir 110 may include multiple tanks for storing different chemicals and one or more pumps for pumping the additives. This supply of additives may be continuous or intermittent.

As shown in FIG. 2, Controller 180 may control operations by utilizing programs stored in a memory 200 associated with the controller 180. The controller 180 may include a microprocessor 210 may have a resident memory, which may include read only memories (ROM) for storing programs, tables and models, and random access memories (RAM) for storing data. The models and/or algorithms stored in the memory 200 may be dynamic models in that they are updated based on the sensor inputs. The microprocessor 210 may utilize signals from downhole sensors received via line 150 and programs stored in the memory 200. Additionally, the controller 180 may transmit control signals to regulating element 130 and other flow devices (not shown), such as flow metering devices, via suitable lines 150. In some embodiments, controller 180 may be a collection of controllers acting in concert to sent control signals to separate groups of production zones.

Referring now to FIGS. 1-2, the assembly 100 may be operated in a number of modes. In some embodiments, the controller 180 may control the operation of the injection device 140 by utilizing programs or algorithms stored in a memory 200 associated with the controller 180. The microprocessor 210 may use signals from sensors, other controllers, or user inputs to determine the appropriate amount of additive(s) to be dispensed into the wellbore.

For example, the controller 180 may receive data indicative of a parameter of interest which may relate to a characteristic of the produced fluid. The controller 180, may then send signals to several different well bores 170 instructing their respective regulating elements 130 to cause the corresponding injection unit 140 to inject different amounts of one or more additives into the production fluid 160 at each of the respective production zones 190.

The parameters of interest may relate, for example, to environmental conditions or the health of equipment. Representative parameters include but are not limited to temperature, pressure, flow rate, a measure of one or more of hydrate, asphaltene, corrosion, chemical composition, wax or emulsion, amount of water, and viscosity. Based on the data provided by the sensors, the controller 180 may determine the appropriate amount of one or more additives needed to maintain a desired or pre-determined flow rate or other desired condition.

As shown in FIG. 3, one embodiment of the disclosure may be implemented with multiple well bores 170, located at multiple drilling facilities 301, each with a production tubular 165. The plurality of regulating elements 130 may control the injection of fluid from the corresponding injection units 140 into corresponding production zones 190. The controller 180 controls the amount and/or substance injected by each of the injection units 140. This configuration is illustrative and exemplary as the disclosure does not limit embodiments to a certain number of production facilities or production zones. Further, additional embodiments may use more than one controller to control injection for a plurality of drilling facilities.

As shown in FIG. 4, another embodiment of the disclosure may be implemented off shore with multiple branched well bores 410 coming off of a well bore 170. A drilling facility 301 mounted over the sea 401 on supports 402 above the sea bed 403 may extend a production tubular 165 into the well bore 170 and branch into multiple branched well bores 410. The plurality of regulating elements 130 may control the injection of fluid from the corresponding injection units 140 into the corresponding production zone 190. The plurality of regulating elements 130 are controlled by controller 180 that may be located at drilling facility 301. Injection into a single production zone in an off shore setting is illustrative and exemplary only. Injection may be regulated for multiple production zones from a single production facility 301. The location of the controller at the drilling facility is also exemplary, as the controller may be located at one particular drilling facility of many or located separate from any of the drilling facilities as long as a regulating signal from the controller can regulate the injection. This embodiment may also be implemented on land as would be understood by one of ordinary skill in the art.

As shown in FIG. 5, an embodiment of this disclosure may be implemented in multiple production zones 190 of a single well bore 170. A controller 180 provides a signal to control a plurality of regulating elements 130, which is located within a production tubular 165 extending from drilling facility 301. Each regulating element 130 corresponds to an injection unit 140, which may have one or more injectors. The controller 180 may be capable of causing the plurality of injection units 140 to inject customized types and amounts of one or more injectable substances into a plurality of production zones 190 separately or simultaneously.

As shown in the FIG. 6, in one embodiment, the rate of chemical injected by an injection actuator valve 600 during each stroke may be determined by the inlet pressure. When inlet pressure is used to determine the rate of chemical injected, a cylinder 660 volume may be reduced through the action of a piston 630, which forces fluid within the cylinder 660 out an outlet port 614 at a desired rate. The desired rate may be determined by the speed of the piston 630 reducing the volume of cylinder 660. The cylinder 660 may be filled on one side when a fluid enters through inlet port 602 and valve rod 640 is positioned by solenoid 620 to allow fluid to enter the cylinder 660. While solenoid 620 holds valve rod 640 in a position to accept fluid into the cylinder 660, solenoid 622 holds valve rod 642 in a position to prevent fluid from entering from inlet port 604 but allow fluid to pass out of outlet port 614. When the power to the solenoids 620, 622 is toggled, then the valve rods 640, 642 change position to allow fluid to enter through inlet port 604, which forces piston 630 to move and force fluid in cylinder 660 out of outlet port 612. The speed of the piston 630 motion through the cylinder 660 may be a function of the difference in pressure between the inlet ports 602, 604 and the corresponding outlet ports 612, 614. Valve rods 640, 642 may include one or more components such that the entire valve rod opens/closes access between the cylinder and an inlet port while it closes/opens access between the cylinder and an outlet port. Since the volume of the cylinder 660 is known, the volume of the fluid injected can be measured and precisely controlled.

In this embodiment, electrical power may only be required for solenoids 620, 622 and not to actuate the piston 630, and this may reduce the amount of electrical energy required to operate the injection actuator valve 600. Reducing the electrical energy burden of actuating a piston electrically may reduce heat in the injection actuator valve 600. In some aspects, the injection actuator valve 600 may be part of the regulating unit 130 and/or part of injection unit 140. In some aspects, the reduction in electrical power requirements may allow a single Tubing Encapsulated Conductor to carry power for multiple additive injector systems and other downhole tools.

As shown in FIG. 7, the injection device may include a variable orifice valve 701 and flow measurement device 702. The additive will flow under pressure through the umbilical 120 to the variable orifice valve 701. A controller will send signals to the variable orifice valve 701 vary the flow rates from off to open. A valve of this type may be used to block the flow of additive through the umbilical 120. Exemplary flow measurement devices 702 include but are not limited to positive displacement flow meters and serve as the regulating element.

In another embodiment as shown in FIG. 8, the injection device may be in the form of a piston device. In this embodiment, a piston 800 moves under pressure from fluid in the umbilical 120 to move past an orifice leading to the wellbore 802. As the piston moves, it compresses a spring 801. Once the piston 800 is clear of the orifice 802, a known amount of additive is released into the wellbore thereby lowering the pressure on the piston and allowing the piston to move back to its original position due to the pressure of the spring 801 and thereby closing the orifice 802. A solenoid or other electrical device 803 holds the piston 800 in its initial position until a signal from the controller releases the piston 800. The flow rate of the additive may be determined by either counting the piston strokes or using the controller to release the piston for a predetermine period of time.

In still another embodiment, as shown in FIG. 9, the injection device may include a memory metal. Memory metals are known to have a first length or volume when exposed to an electrical current and a second length of volume when not exposed to an electrical current. In FIG. 9, a memory metal device 900 may be used to block an orifice leading to a wellbore 901. A controller may be used to send a current to the memory metal 900 causing it to shrink and allow a flow of additive to a wellbore. In an alternative embodiment, an electrical current is maintained in a memory metal 900 blocking egress of additive to the wellbore and the current is discontinued to allow a flow of additive to a wellbore. In this embodiment, a metering pump at the surface or downhole serves the purpose of the regulating element.

An alternative embodiment similar to that illustrated in FIG. 8 is shown in FIG. 10. As in FIG. 8, the injection device may be in the form of a piston device. In this embodiment, a piston 800 is held in place by a spring (not shown) thereby blocking the orifice 802. In this embodiment, the piston 800 is moved up a rather than down by a solenoid or other electrical device 803. Once the piston 800 is clear of the orifice 802, a known amount of additive is released into the wellbore. The solenoid or other electrical device 803 holds the piston 800 in its raised position until a signal from the controller releases the piston 800 allowing it to close or block the orifice. The flow rate of the additive may be determined by either counting the piston strokes or using the controller to release the piston for a predetermine period of time.

While the foregoing disclosure is directed to the one mode embodiments of the disclosure, various modifications will be apparent to those skilled in the art. Especially the illustrated injection devices may be combined with the regulating elements in combinations differing from the drawings. It is intended that all variations within the scope of the appended claims be embraced by the foregoing disclosure. 

1. An apparatus for controlling an amount of an additive injected into a plurality of production zones or points within a single production zone, comprising: a plurality of additive injector assemblies, wherein each injector assembly comprises: an umbilical disposed in a wellbore intersecting a production zone, at least one injector device adapted to receive the additive from the umbilical and disposed within the production zone, and a regulating element associated with the at least one injector that is responsive to a control signal; and at least one controller configured to transmit a plurality of control signals to the plurality of regulating elements.
 2. The apparatus of claim 1, wherein the plurality of regulating elements include electromechanical devices.
 3. The apparatus of claim 2 wherein the electromechanical devices are selected from the group consisting of solenoid actuated pistons, variable orifice valves, memory metal devices and combinations thereof,
 4. The apparatus of claim 1, wherein the at least one controller is located on the surface of the earth.
 5. The apparatus of claim 1, wherein the amount of additive introduced to at least one of the plurality of wellbore zones is controlled by the at least one controller through at least one of the plurality of regulating elements.
 6. An apparatus for controlling an amount of an additive injected into a plurality of production zones, comprising: a plurality of additive injector assemblies, wherein each injector assembly comprises: an umbilical disposed in a wellbore intersecting a production zone, at least one injector adapted to receive the additive from the umbilical and disposed within the production zone, and a regulating element associated with the at least one injector that is responsive to a control signal, wherein each of the plurality of regulating elements controls the amount of additive introduced to each of the plurality of wellbore zones, and wherein the plurality of regulating elements are electromechanical; and at least one controller configured to transmit a plurality of control signals to the plurality of regulating elements, wherein the at least one controller is located on the surface of the earth, and wherein the amount of additive introduced to at least one of the plurality of wellbore zones is controlled by the at least one controller through at least one of the plurality of regulating elements.
 7. A method for controlling an amount of an additive injected into a plurality of production zones, comprising: introducing a plurality of additive injection assemblies into a plurality of wellbore zones; wherein each of the plurality additive injection assemblies comprises: an umbilical disposed in a wellbore intersecting a production zone, at least one injector adapted to receive the additive from the umbilical and disposed within the production zone, and a regulating element associated with the at least one injector and responsive to a control signal, wherein the regulating element controls the amount of additive introduced to the wellbore zone, and activating at least one controller in communication with the plurality of regulating elements send at least one signal to at least one of the plurality of regulating elements.
 8. The method of claim 7, wherein the amount of additive introduced to at least one of the plurality of production zones is dissimilar to the amount of additive introduced to another one of the plurality of production zones.
 9. The method of claim 6, wherein the plurality of regulating elements include electromechanical devices.
 10. The method of claim 9 wherein the electromechanical devices are selected from the group consisting of solenoid actuated pistons, variable orifice valves, memory metal devices and combinations thereof,
 11. The method of claim 7, wherein the at least one controller is located on the surface of the earth.
 12. The method of claim 7, wherein the amount of additive injected into at least one of the plurality of production zones is controlled by the at least one controller through at least one of the plurality of regulating elements.
 13. A method for controlling an amount of an additive injected into a plurality of production zones, comprising: supplying the additive to a plurality of injectors; wherein each of the plurality of injectors is disposed within one of the plurality of production zones; transmitting a plurality of control signals from at least one controller to a plurality of regulating elements, wherein each of the plurality of regulating elements is associated with at least one of the plurality of injectors; and injecting the amount of additive into the plurality of production zones responsive to the associated control signal.
 14. The method of claim 13, wherein the amount of additive introduced to at least one of the plurality of production zones is dissimilar to the amount of additive introduced to another one of the plurality of production zones.
 15. The method of claim 13, wherein the plurality of regulating elements include electromechanical devices.
 16. The method of claim 15 wherein the electromechanical devices are selected from the group consisting of solenoid actuated pistons, variable orifice valves, memory metal devices and combinations thereof,
 17. The method of claim 13, wherein the at least one controller is located on the surface of the earth.
 18. The method of claim 13, wherein the amount of additive injected into at least one of the plurality of production zones is controlled by the at least one controller through at least one of the plurality of regulating elements. 